Sunlight in the Shadows
by WitandAmbition
Summary: Hallie Potter knows two things: Regulus Black is more annoying than her brother, and war is approaching. Can a Gryffindor and a Slytherin ever get along? (AU, Hallie is James' little sister.)


**Disclaimer: Harry Potter belongs to J.K. Rowling. I make no claims to ownership.**

_**Prologue: The Beginning**_

Platform Nine-and-Three-Quarters was filled with people, the Potter family among them. At the moment, Mrs. Potter was fussing over her son. Hallie stood next to them, tuning out her mother's lecture as she tried to see who among the crowd was a first-year.

"And make sure you watch over your sister –"

"Mum, honestly, Hallie can fend for herself, can't she?"

Here, James shot a grin at his little sister, who finally tore her gaze from the bustling crowd around them. With her messy black hair and hazel eyes, Hallie looked like a younger, female version of James. She had been born sixteen months after him, and James enjoyed rubbing that fact in her face at every opportunity.

"Sure," she said, and then paused. "Er, what were we talking about?"

Their mother huffed. "You see, James, _that_'s why you need to look out for your sister."

As James opened his mouth, Hallie's attention was drawn to a family which had just stepped onto the platform. The man and woman wore extravagant robes made of silk and their two sons were similarly dressed. Hallie guessed that the people giving the family odd looks weren't pureblood. Otherwise, they would recognize the infamous Black family.

A shiver passed down Hallie's spine. She could easily recognize those sharp and aristocratic features, for they were the same features she saw in the mirror.

The Black family was drawing closer to them, and Hallie's mother suddenly ceased her lecture. Her hand latched onto James' shoulder when he made to turn around.

"Dorea," Mrs. Black said stiffly.

"It's Euphemia," said Hallie's mother with the same forced politeness. "You know that, Walburga."

As if her mother had never spoken, Mrs. Black looked at Hallie and said, "Is this your daughter's first year, then?"

Hallie dropped into a curtsy.

"Good day, Auntie Walburga," she murmured.

Mrs. Black's eyes glittered with approval. "I see your daughter has manners," she said. "Even if your son does not."

"Mother," Sirius started, only to have his father put a staying hand on his shoulder. Unlike James, who was almost shaking with repressed energy, Sirius schooled his features into a blank mask.

Hallie had heard rumors of Mr. Black. He was a year younger than his wife, and their parents had forced him to marry her. In his own way, he cared about his sons. He just didn't know how to show it. At least, that was what her mother claimed.

Beside Sirius, his brother shifted nervously. Something about the action struck a chord within Hallie, and before she knew what she was doing, she had stuck a hand out to him.

"Hi! I'm Hallie Potter. Are you a first-year, too?"

The boy looked at her hand with horror.

"Harriet," her mother hissed.

"It's fine, Mia," said her father. "I'm sure Hallie and Regulus will be good friends, won't they?"

Hallie maintained her frozen smile. Finally, a nudge from his mother had Regulus shaking her hand in a very mechanical motion. He released his hold at once.

"I hope you'll be in Slytherin, Harriet," said Mrs. Black.

Hallie didn't know how to respond, so she was very glad when her father said, "We'll be proud no matter what House she chooses," and took the attention off her.

At last, the two couples finished their stiff pleasantries. As the Black family walked away, Sirius glanced back over his shoulder and sent James a wink. Hallie blushed even though the wink wasn't directed at her.

"Mum's right," said James. "You _do _need someone to look out for you."

This time, Hallie's face turned red for a completely different reason.

"I do not," she snapped, and stuck her nose in the air for emphasis. "No one needs an idiot like you around."

"Oh, _I'm_ the idiot, am I?"

"Children," said their father in a warning tone. "You have the rest of your lives to bicker with each other. Let's be nice right now, okay?"

"Yes, Dad," they chorused.

Just then, the train blew a warning whistle, and their mother drew them into a hug. Hallie could feel James' messy hair poking her in the face and she blew against it. James immediately wiggled away from her.

"Don't do that," he growled, sliding a hand through his hair.

"Be nice," their father warned again, and both Hallie and James looked at their feet. In a gentler tone, he added, "Now come here and give your old man a hug."

"But Dad, my _reputation_…" James whined.

"_I _love you, Daddy," Hallie declared, hugging him tightly.

He smiled. "I love you too, princess."

Grumbling about devious little sisters, James embraced their father, too, and even allowed their mother a second hug. Then he leaped aboard the train and with a cheerful wave, disappeared down the corridor. Once he was gone, Hallie looked up at her parents.

"What if I'm in Hufflepuff?"

They exchanged a look.

"You're not worried about Slytherin?" her mother asked after a moment.

Hallie shrugged. From what she understood, James didn't particularly care about Slytherins one way or the other. He only hated one boy, whom he referred to as Snivellus. Apparently the other boy had declared himself a racist and then insulted James for wanting to be in Gryffindor. With their uncle being a Squib, James was very sensitive to racist bigotry.

"Not really," Hallie confessed. "But James said Hufflepuffs are stupid, and he says I'm stupid all the time…"

"Hufflepuffs aren't stupid, nor are you," her father said. "Don't make snap judgements on _any_ House, Harriet. It will only get you into trouble."

Then he bent down and crooked a finger for her to come closer. Hallie did so, eager to know the secret.

"If James is saying something like that," he whispered conspiratorially, "maybe he has a crush on someone in Hufflepuff."

Her eyes widened. "You think so?"

"It's a possibility," he answered with a shrug, and then he looked up at his wife with a grin. "Isn't that right, Mia?"

"It certainly is, Monty." Her mother bent down too, her gray eyes shining with humor. "Your mission, should you choose to accept it, is to discover James' crush. Do you think you can do that, Hallie?"

She nodded her head vigorously. "I can, Mummy!"

Then after one last round of hugs, she jumped onto the train and leaned out the window, waving at her parents. Other students crowded around her, doing the same. Hallie waited until her parents had faded from view before setting off to find her trunk. Her father and brother had loaded the trunk onto the train for her, into a compartment nearby James.

Hallie smirked to herself. Despite his protests, James really did care about her.

Suddenly, she came to a stop. Inside the compartment where her trunk had been deposited was a boy with dark hair, his head bent over a book. After a moment, she gathered her wits and she slowly slid open the door. Regulus looked up as she entered, his eyes first widening and then narrowing.

"I knew it," he growled, slamming his book closed. "I'm going to _kill_ him."

Coming from a Black, Hallie knew that was no idle threat. When he tried to shove his way past her, she deliberately blocked him. He froze as she put her hands on his chest and his expression tightened with something like disgust.

"Hey, er, killing's bad, you know?" she said, tilting her head back just slightly. He had about an inch on her, which in no way made him superior.

"Oh, I know," he snapped without looking at her, venom dripping from his words. "And I know how _badly_ I want to kill him."

"Or you could kiss him," she offered.

His gaze swung to her, and for the first time, she realized how close they were standing. Heat flooded her face, but she refused to back away. Hallie was all that stood between Regulus Black and someone's death.

"Kiss my _brother_?" he said incredulously.

"Or you could, er, hug him," she said, blushing even more.

He huffed at the idea. "Out of my way, Potter," he said, grabbing her wrists and pushing her away. "I'm not going to kill my brother in _public_."

That didn't ease her worry at all, but he was stronger and she couldn't stop him from sliding past her. Hallie watched him walk down the corridor in the opposite direction of their brothers' compartment. She knew with certainty that Regulus Black would be the bane of her existence, and she was going to return the favor.

"You could still try hugging him," she called after him, and felt a modicum of satisfaction when she saw his thin shoulders tighten with annoyance. As James could assure anyone, Hallie could be the biggest pest when she wanted. Soon, she would make sure Regulus knew that, too.

* * *

The Sorting went as she expected. James reached over to congratulate her as she joined him at the Gryffindor table, even consenting to a hug in public. He seemed confused when she clung to him longer than usual.

"Is Regulus looking?" she whispered into his ear.

"No," he said. "Why'd he be looking?"

She huffed. "Never mind."

"Excuse me," said the Prefect between them. "I'd like some space here."

Disappointed, Hallie released her brother and sank into her seat.

By the end of the Sorting, she was among ten new students in Gryffindor. The Prefects, Frank Longbottom and Louisa Pyke, informed them of the dormitory rules on the way up to the tower. Hallie nodded along with her peers, even though she already knew this information from James.

"He's so full of himself," whispered Edith Longbottom.

"Who?" Hallie asked, immediately thinking of her brother.

"Frank. Look at him, he thinks he's so important now."

Ahead of them, Frank was talking normally as he gestured to another passageway. Hallie didn't see any arrogance in him, but she agreed with Edith anyway. After all, only a little sister could know her brother so well.

"My brother's a year older than me," she said. "He thinks it makes him superior."

Edith shared a conspiratorial grin with her. "But we know it doesn't."

Both of them giggled, but at a look from Frank, they went silent. He narrowed his eyes at his sister, who only looked innocently back at him. With a roll of his eyes, he turned back around and picked up Louisa's explanation. Edith nudged Hallie and they giggled again.

Finally they reached the tower, where they were directed to separate dormitories. After getting into bed, Hallie stared up at the canopy above her and reflected on the role of brothers. Maybe Regulus didn't like his own older brother, but sometimes, Hallie really appreciated James. In a way, he had helped her plant the seeds of friendship with Edith. She'd never tell him, though, lest it go to his head.

Pleased, she rolled over and closed her eyes. With today being Friday, classes wouldn't start for another three days. Over the weekend she would get to know her roommates and, hopefully, they would become good friends like James was with Sirius, Remus, and Peter.


End file.
